Macular degeneration is a disease in which degeneration occurs in the macula which is a nerve tissue located in the center of the inner retina of the eye and causes vision impairment, and since most of the photoreceptors are gathered in the macula and a place where an image of an object is formed is also at the center of the macula, the macula plays a very important role in vision. The most common cause of macular degeneration may be an increase in age (age-related macular degeneration), and is known to be related to family history, race, and smoking. Because the macula is responsible for central vision, if degeneration occurs in the macula, a decrease in vision, central scotoma, metamorphopsia which is a symptom in which things appear distorted, and the like occur. Macular degeneration is largely classified into non-exudative (dry) and exudative (wet), and the non-exudative macular degeneration does not significantly affect vision in most cases, except for the late stage when the atrophy of the retina and the choroid appears, and is a step in which yellow deposits called drusen are seen under the retina, but in the case of the exudative macular degeneration in which subretinal hemorrhage or subretinal fluid, pigment epithelial detachment, and the like appear, when the position of such a lesion is present under the macula or immediately adjacent to the macula, a drop in vision appears from the initial stage. The exudative macular degeneration accounts for about 10 to 20% of the total cases of macular degeneration, but if the exudative macular degeneration is left as it is without being treated, vision rapidly deteriorates, so that many patients will be blind within two years after being diagnosed with the exudative macular degeneration. In order to prevent macular degeneration, it is important to find an abnormality of the macula early through a periodic funduscopic examination and to make an effort so as to reduce the adjustable factors such as obesity, smoking, and hypertension. Since smoking causes damage to choroidal circulation leading to a drop in antioxidant factors in blood and causes choroidal vasoconstriction to cause low oxidative damage, a patient who is at risk of macular degeneration necessarily needs to quit smoking. Further, since a macular pigment (lutein, zeaxanthin) reduces damage caused by aging and serves to maintain a healthy retina, sufficiently ingesting the macular pigment through vegetables and fruits or taking commercialized vitamin supplements can help in the prevention of macular degeneration.
The macular pigment serves to reduce age-related failing eyesight caused in the central part of the retina and prevent retinal tissue damage due to bright light, and representative examples thereof include a xanthophyll as a carotenoid-based oxycarotenoid pigment produced by oxygenation of a carotenoid. Examples of a pigment belonging to xanthophylls include lutein, zeaxanthin, or the like. It is known that lutein acts as an antioxidant that protects the inside of the eyes that is damaged by free oxygen radicals naturally produced in the body, reduces the growth of blood vessels that supply carcinomas to kill cancer cells, and has some effects on prevention of breast cancer, colon cancer, lung cancer, ovarian cancer, and skin cancer.
Animals cannot produce xanthophylls and can obtain xanthophylls only through ingestion of food, but these xanthophylls are present together with chlorophylls and carotenes in the green parts such as leaves, flowers, and fruits of plants. Recently, a health functional food for eye health, including xanthophylls, and the like has attracted attention.
Existing marigold flowers are representative as a raw material for zeaxanthin and lutein, and those extracted from other higher plants has also been studied. In addition, zeaxanthin and lutein are also produced by genetically mutating the pigment synthesis mechanism in bacteria. Studies have also been conducted to obtain these pigments from microalgae. Among these conventional raw materials, marigold flowers have a disadvantage in that it takes a long time to breed flowering plants for production, and have a problem in that the production unit cost is high because the production amount is not large as compared to the land area for production.
In order to solve these problems, the development of zeaxanthin and lutein-producing algae into which a pigment synthesis mechanism is inserted using a bacterial system for replacing a higher plant system was carried out, but there is a problem in that a pigment obtained from bacteria is not suitable for ultimate use as a food additive. In addition, since genetically modified organisms (GMOs) using a genetic insertion technology and the like are not preferred in the domestic market, the GMOs act as a fatal disadvantage in the food additive marker where consumers' perceptions are important, and likewise as in the higher plant system, there is a problem in that a large cost of maintaining a bacterial culture solution, a bioreactor, or the like may be required.
In the case of a method of obtaining these pigments from microalgae, the conventional microalgae are a wild type which is not improved, and have a limitation in being used as optimal producing algae because the content of lutein is constant, but the content of zeaxanthin is very low depending on the amount of light.